Question

what is the effects of NH3(aq) and HCl(aq) on the CuSO4 or NiCl2 solution

Answer 1

It isn't clear what solution you are talking about but NH3 complexes both Cu and Ni for form Cu(NH3)4^2+ and Ni(NH3)4^2+. If the HCl is added to these complexes the NH3 is neutralized and the original Cu ions and Ni ions are formed. Concentrated HCl will form CuCl4^2- and NiCl4^2-